Physics diffraction

how does wavelength affect the amount of diffraction

Increasing wavelength increases the diffraction up until when wavelength is greater than the slit width

What are examples of wave behaviour

Interference, diffraction

Examples of particle behaviour

Mass, momentum, photoelectric effect

What determines if something acts like a particle or wave

When de broglie wavelength is larger than the particle, it acts like a wave

Single slit diffraction pattern

A single bright fringe of double usual width, then slits of much lower equal intensity equally spaced

How to set up double slits

Set up a laser in front of a single slit, with double slit behind it so the light hitting the slits has 0 path difference and coherent

Why are lasers helpful in double slit experiments

They provide a source of monochromatic coherent light, so patterns can be clearly seen

Uses of diffraction gratings

reading optical drives

Spectral analysis of stars

What is the path difference of the waves at the dark fringes

n/2 * lambda

What is the path difference at bright fringes

n * lambda

In double slit, why do dark fringes and bright fringes form

At bright fringes. the waves superpose and constructively interfere at bright fringes and destructively interfere at dark fringes

What does single slit diffraction interfere with

It interferes with the waves from different parts of the slit

Double slit interference pattern

All are equal width with a high intensity central maximum, fringes much closer together than single slit

Ways to produce monochromatic light (without laser)

Discharge lamps, filters of white light

How many maxima are produced when d/lambda = 3.2 in a diffraction grating

7 (central maxima and 2 sets of 3 maxima)

Why can’t we calculate fringe spacing for diffraction grating

Because the fringes arent equally spaced

Why are there large areas of dark in diffraction gratings

Because at these positions all the different waves superpose and cancel each other out, it is lots of waves to constructively interfere

Double/single slit pattern with white light

A central white maxima, with fringes showing the colour spectrum from red closest to the outside and violet on the inside, with the spectra becoming wider further from the central maxima, shrinking the dark fringes

Diffraction grating with white light

Central white maxima, with spectra with violet on inside and red on outside where maxima would be. Maxima increase in width with increasing order.